Need Advice. 40 years later, my natural child who was adopted by another family, is trying to connect with me.

40 years later, I am delighted that my natural child who was adopted by another family, is trying to connect with me. Back in the 80's, in the course of the adoption my partner and I signed away all rights and were told not to be in contact with the child at all. Well it is 40 years later and my natural child is initiating a connection with me via email. Do I need to first get permission from the adoptive parents (if they are still alive), or is it OK to communicate with her?